MXPA99006533A - Hypodermic injection system - Google Patents

Abstract

This invention is in the field of the injection of liquid into tissue by generating a high pressure jet capable of passing through the skin. It is concerned with a hypodermic injection systemfor liquids comprising a medication container in which the liquid to be injected is located and which has two regions whereby the first region is squeezable or flexible and the second region contains at least one exiting orifice through which liquid can escape. The flexible region can be deformed by a pressure change in a surrounding container generated by an activatable gas generator and liquid is forced through at least one exiting orifice from the first container. This invention is also directed to means for controlling the pressure of the liquid jet, as well as medication containers which enable a sterile injection of medication.

Description

HIPODERM A INJECTION SYSTEM This invention is in the field of the injection of a liquid into the tissue by generating a high pressure jet capable of passing through the skin. The hypodermic injection system for fluids, comprising a unit of the medicament in which the liquid to be injected is stored and having a first and a second region, the first region that is compressible or flexible and the second region having at least a hole, - an explosion chamber in which the drug unit is located at least partially and a pressure generated within the explosion chamber is deforming the first region of the drug unit, an activatable gas generator, located within the explosion chamber, which generates a pressure inside an explosion chamber when activated, an activation unit to activate the gas generator, Ref .: 30814 where the explosion chamber has a gas outlet opening connected to a free volume camera that has a variable volume. A further aspect of the present invention are the units of the medicament which ensure that the liquid medicament is not in contact with the non-sterile portions of the medicament unit or the injection system prior to introduction to the skin. In the field of medicine there are numerous methods for the administration of a total amount of medicines. The forms of administration of the medicine such as tablets, dragees, creams and the like are all known. For a plurality of active ingredients such administration forms are inadequate because the physiologically active ingredient degrades before they can become active. In the tablets which must be taken orally, the medication, for example, has to be constructed such that it is resistant to the aggressive acids of the stomach and on the other hand it can be resorbed by the stomach or the intestinal wall in the circulation of the stomach. blood. For a large number of medicines it is not possible to develop a favorable administration form for the patient such as a tablet or a lozenge. Therefore, in such cases it is necessary to introduce the medicine directly into the body tissue or into the vascular, blood system. Nowadays it is a usual practice for the injection to occur using a syringe. However, in the prior art it has been known for a long time that the injection devices can be operated without using a hollow needle which is not comfortable for the patient. Injection systems without a hollow needle employ a liquid jet which is ejected at high velocity from a hole and is capable of penetration through the skin and tissue. Such an injection is significantly less painful and can be performed by personnel who have not been trained in the use of syringes. Injection systems that employ a jet of pressurized fluid of medication which penetrates the skin are called hypodermic injection systems within this application. The hypodermic injection is implied to include intradermal, subcutaneous, and intramuscular injections. With an injection system according to the invention, all available drugs can be injected in liquid form. The field of application covers, for example, drugs for pain relief (analgesics), insulin and also protein solutions. For protein solutions, especially human protein solutions, it has been remarkably discovered that these can be administered substantially without any degradation by means of a high pressure jet. Needle-free injection systems were described in the 50s and 60s. In the US Patents Nos. 2,322,244 and 3,335,722 devices have been described, which use explosive substances for the generation of the high pressure jet, necessary. The current systems, such as, for example, Vitajet® from the Vitajet Corporation, employ a steel spring or spring for the generation of the high-pressure jet. A device which operates in an analogous manner is also marketed by Mediject Corporation. Such systems have the disadvantage that the user has to perform several complicated, operational steps. First of all, the liquid to be injected is introduced into the injection device. Then a spring or steel spring is pressed by the rotation of parts of the device against each other. Especially for people who are sick or equally many diabetics who are physically disabled, the necessary operational steps require the application of enormous effort. An alternative to this system is offered by the injection systems mentioned above that use explosives, because the energy of the explosive substance is used and a complicated spring or spring pressure is not necessary. The rejection of such systems, which have taken place in the course of time, is directly related to the serious disadvantages with respect to hygiene and technical safety aspects. U.S. Patent No. 3,335,722 discloses that the reciprocal contamination of explosives and medicines is a particular problem of such constructions. In the North American patent, an order is suggested, in which the capsules containing the medicine and the explosive substance are separated from each other and a special arrangement is used for the transfer of energy. In the order described, an explosive is ignited by a contact bar, as is the case, for example, with a rifle bullet. The gas resulting from the explosion accelerates a piston which is mechanically attached to a second piston which accelerates a rubber plunger which in turn forces a medicinal fluid out of the hole on the opposite side. In order to prevent the reciprocal contamination of the combustion gases and the medicine, complicated technical constructions are necessary, which disadvantageously complicates the injection device and make it more expensive. In addition, an ampule in which a rubber plunger is driven is required. Due to the pressure in the ampoule, created by the movement of the plunger, it is necessary to make arrangements that ensure the prevention of leakage between the ampoule and the plunger. In this respect, the selection of the material for the ampule is critical, because a deformation when pressure is applied should not lead to leakage in the region of the plunger. The devices described in the prior art all exhibit in general the disadvantage that for the generation of pressure parts that can be compressed together, plungers are used and therefore the sealing areas have to be controlled. Known devices for a free injection of liquid needles which avoid emboli or the like are also known in the prior art. European patent application No. 0 370 571 describes a system where a vial containing a liquid medicament must be mechanically compressed by a rod. This compression drives the liquid medication through one or more orifices to generate a jet of fluid. While this apparatus for the most part avoids the problems associated with frictional surfaces and pistons moving in a cylinder, this apparatus has a disadvantage that the flexible part of the ampoule can be destroyed when pressed by the bar. A further disadvantage of this device is that the pressures that can be applied to the ampule are limited due to the risk of destruction and also by the relatively low energy stored in the spring or spring. Another disadvantage of this apparatus is that a mechanical compression of the ampule by a bar can not guarantee that the liquid inside the ampoule is completely expelled. Therefore, such a device is insufficient when it is desired to inject a specific amount of medicine. In document FR-1,121,237 a device for the hypodermic injection of liquids using a jet of highly pressurized liquid is described. The device comprises a compressible container for liquid medication, which is attached to a unit that has a fluid channel. The unit with the fluid channel is connected to a unit with a nozzle so that a continuous channel must be formed through which the liquid medicament can be expelled. For a hypodermic injection, the unit with the channel is placed in a mounting element so that the container with medicament is surrounded by a chamber and pressure is applied to the chamber by the ignition of an explosive. The apparatus described in FR-1121.237 seems very similar to the present invention but has some technical disadvantages that are overcome by the present invention. FR-1,121,237 teaches that the drug container and the unit with the channel are combined by the user. The user fills the liquid to be injected into the medication container and hermetically closes the medication container by screwing in the unit with the fluid channel. Such a process alone is not only uncomfortable or difficult to manage, but also carries the risk that the drug and / or the fluid channel become contaminated. The injection of a contaminated medical fluid is totally unacceptable in the therapeutic field. This problem of contamination is in most cases unresolved in the prior art of the hypodermic injection of liquids. In addition, document FR-1.121.237 does not give any information regarding the pressure of the liquid jet and how this pressure can be controlled to be in a specific range or how the pressure can be changed by the user to meet their needs specific. A further disadvantage of the system described in FR-1121 237 is that no means is described for purging the air from the liquid chamber. However, air within the liquid chamber leads to disadvantageous effects as described further below. Reference GB-697,643 describes a device for hypodermic injections using a flexible or collapsible element which must be compressed. The device described in this document is very complicated and uses a rechargeable pressure chamber in which a pressurized gas is introduced and in addition to this a chamber with a hydraulic fluid is used. With this device it is possible to control the pressure by which the liquid must be expelled from the container. However, a flexible container is necessary in which the collapsible medication container must be inserted. From the function of this device it must be assumed that it is impossible to expel all the fluid which is inside the medication container. GB-697,643 further describes a medicament container which is sealed and can be used to store a medicament under sterile conditions. However, this document does not disclose a medication container that includes a sterile mouthpiece. Therefore, this document does not give a total solution to the goal of sterile injection. A device for hypodermic injections is also known in the prior art as described in U.S. Patent No. 3,308,818. A flexible medicine container should be placed in a chamber and pressure should be applied to this chamber by an explosive to compress the medicine container. While compressed, the medication container breaks at the entrance of a fluid channel which ends in a hole. The fluid is then expelled from the flexible containers through the fluid channel and injected into a human or animal. This very simple device has a number of disadvantages compared to the present invention. U.S. Patent No. 3,308,818 of prior art does not describe how to control the pressure generated by the explosive. In addition, the device uses an area in which the wall of the flexible container breaks when it is pressurized. The disadvantage of such uncontrolled rupture is that small particles which are introduced together with the liquid medicament into the body can be discharged from the flexible container. The injection of such particles can cause inflammations or allergic reactions. Another disadvantage of the system described in the North American patent No. 3, 308,818 is that the fluid channel and the nozzle through which the medicament is expelled, are not maintained under sterile conditions. Therefore, injections with such a device can lead to infections or inflammations. The prior art generally describes pressurizing a flexible drug container to expel a jet of liquid that is capable of penetrating the skin. However, even if this concept has been known for a long time, a system which uses this concept is not available in the market. This shows that there are still technical obstacles that have to be overcome. The present invention describes a system for hypodermic injections and drug units which overcomes these obstacles. The aim of the present invention was to provide an economically acceptable but nonetheless reliable device for needle-free liquid injection. In particular, it was the object of the invention to exclude with certainty the reciprocal contamination of explosion gas and medicine by the use of a simple medium. Furthermore, it was an object of the present invention to provide an injection device which can be operated by the user with a minimum of inconvenience and which is also simple in construction as well as economically acceptable. This invention proposes injection systems and medication unit which avoid the contamination of a liquid medication before the penetration of the skin. An additional problem which is solved by this invention is the control of the pressure of the liquid jet. In the injection system of the present invention, the frictional surfaces and the sealing surfaces between the moving parts of a medicament container are avoided. Instead of these, a unit of the drug is used which has a region which can be pressed together or is flexible and can therefore be deformed. This region involves the liquid medication to be expelled. The medication unit also has a second region with an orifice through which the liquid medication can escape from the drug unit when the first region of the drug unit is deformed. The use of such a medication unit has the advantage that parts which have to be slid together are avoided, and the sealing surfaces between these parts are avoided. To facilitate compression or pressure together of the medication unit, the container is located in a container, which encircles the compressible region of the medication unit at least in part or adjoins the drug unit with its flexible region such that a change pressure in the container leads to a deformation of the flexible region. When pressure develops within the container, pressure develops similarly in the medication container whereby also the liquid is forced out of the hole. The first region of the medicament unit is preferably made of materials that can be easily deformed, such as plastics or metal sheets. For the generation of the effect according to the invention, it is important that due to compression or deformation the components are not mechanically forced against each other such that frictional surfaces are caused, the sealing of which is difficult to handle. The coating of the container in the first region remains closed during pressure together with the components or the deformation step or deformation that is possible due to the elasticity of the material in the first region. The deformation may result, for example, from the joint pressure of a section of a wall whereby the elasticity of the wall material is used to ensure that the outer coating of the container remains closed. However, this is associated with a relatively strong mechanical tension of the wall which can be reduced in the modalities in which a compression of the wall material results or in which the wall moves convexly to a concave shape . In the last modality mentioned, the surface of the first region in both forms is generally the same as to prevent the expansion and severe contraction of the wall material. In the embodiments described above, severing and severe stretching of the wall material in the first region of the medicament unit is virtually avoided in its entirety. Therefore, usually the wall material can have modest mechanical properties, since it must only withstand low stresses. Plastics such as polyethylene, polypropylene or PVC are, for example, suitable, with which the thickness of the wall of less than one millimeter can be achieved. Particularly suitable wall thicknesses are in the region of 100 to 600 μm. Metal sheets having a thickness in the range mentioned above can also be used. The unit of the drug has a second region in which an orifice is located for the expulsion of liquid. For this purpose, an outlet channel is located on the side of the second region leading to the orifice. departure. The second region is also mechanically stable to such an extent that no significant deformation occurs as a result of the pressure developing in the first container. Alternatively, if deformation is predictable, it can be allowed in the design. A proper geometric ordering should prevent the deformation of the exit orifice. However, even such deformation can be allowed if it is considered in the design. A suitable diameter of the hole is known to those skilled in the prior art. When explosive substances are used, extremely high pressures can be generated such that smaller openings in the region of 80 to 130 μm are acceptable. These openings of the exit orifice are smaller than those of the prior art and the injection is less painful. There are no special requirements with respect to the geometric shape of the exit channel and the exit orifice. However, a form in which the liquid jet is focused is advantageous. Particularly useful types of drug units that include advantageous orifices are described further below. For reasons of hygiene, it is necessary to close the outlet hole to prevent leakage and contamination of the liquid in the first container. Preferably, such closure is achieved by a knob / leg or the like which is connected to the second region by a predetermined breaking point. In addition, screw caps, lids and the like can serve this purpose. The first and second regions of the first container are advantageously formed as an individual unit which, however, can comprise two or more parts. The first container can be manufactured in particular as a unit, similar to the known designs for eye drop ampoules. First of all, the second region containing the outlet channel is formed in an injection molding process to which an open plastic cover is connected which then takes the form of the second region. The liquid is filled in the plastic cover and the opening is sealed when welding the cover material. The system of the invention is advantageously constructed such that the act of joint compression or deformation occurs only in the first region and no deformation occurs in the second region. Similarly, the transition region from the first to the second region should also be subjected, as far as possible, to little deformation.

In an advantageous embodiment, the first compressible region of the medicament unit is completely located within a surrounding container. In addition, it is favorable when the surrounding container is completely closed by the drug unit and possibly the additional material components, such that the gas can not escape even when there is a higher pressure outside the system than in the environment. When the gas pressure increases very rapidly, for example by the rapid combustion of an explosive substance, it is not necessarily required that the surrounding vessel be completely closed to the environment. It is also possible to provide small openings through which the gas can escape. When the gas is generated very quickly, the creation of pressure in the surrounding vessel is so rapid that no significant pressure drop takes place during the explosion process. According to the invention, a joint pressure or compression of the first region of the drug unit occurs. The pressure outside the surrounding vessel drops only slowly as a result of gas leakage. Such an embodiment of the injection system can be of advantage when the combustion gas contains mainly constituents which do not condense at room temperature because in such cases the high pressure would remain in the second container after the use of the injection system. This is usually disadvantageous, but can nevertheless lead to deformation of the container in the embodiments having a second thin-walled container which is disconcerting to the user. If the gas generators are used where the amount of substances condensing at room temperature is greater than after the use of the system for injection, a significant excess of pressure does not remain in the surrounding vessel, then the openings in the surrounding vessel they are not usually necessary. A further aspect of the present invention are the drug units suitable for hypodermic injection. Such units of the drug have to meet some specific needs: These have to ensure that the medicine injected into the body does not come into contact with the non-sterile parts of the drug unit or the injection system before entering the skin . Another requirement is to avoid substantial amounts of air or gas in the medication unit. It is expected that most of the air will escape between the mouthpiece and the skin during the injection, but air could be carried down the skin if the mouthpiece is strongly pressed against the surface of the skin. Additionally, the gas or air inside the medicament unit can cause interruptions in the jet stream and the fluid moves perpendicular to the direction of the current which can lead to incomplete injections or disadvantageous jet profiles. In addition, the medication unit must ensure that the medication can be injected as completely as possible to control the amount of medication supplied to the user. It is an additional requirement for the medication containers that they be made of a material that does not affect the medication even if the medication is stored for a period of months or years. It has proven advantageous to employ units of the medicament which are made of polyethylene, polypropylene or mixtures thereof since these materials do not affect the liquid medicaments that have been tested. Since these materials have a low modulus of elasticity (these are soft), it is a further object of the present invention to provide nozzles that can withstand the pressure during the injection process. The prior art devices for jet injections employ nozzles made of hard plastics such as polycarbonates, metals or ceramics. It has been shown that it is of particular advantage to produce the units of the medicament with the so-called blow-fill-seal process. This process leads to drug units that contain only very little gas. The blow-fill-seal process generally comprises the following steps: a softened plastic tube is closed at its lower end by compression. pressure is generated inside the tube to press the softened plastic against the walls of a mold to form an open end container, - the liquid medicament is filled in the open end container, the container opening is closed by compression and is fixed (for example with ultrasound or hot tongs). The process described above is well known in the art and for example described in more detail in "Plástic Mold Engineering Handbook" 4th ed., Pp 540-545, Van Nostrand Reinhold, New York (1987) and DE 4439231. Bubble-free, complete filling of vessels produced by the normal sealing-filling-sealing process is not possible because the seal of the upper end of the container has to be made in a dry area to form a reliable weld. Therefore, a volume on the liquid should be left empty. This results in an air bubble inside the container. Within most applications such an air bubble is not of consequence, as for example in the case of containers of eye drops. However, air bubbles are undesirable inside the medication containers for hypodermic injections as explained above. Therefore, the present invention describes new processes for the production of drug units for hypodermic injectors that avoid air bubbles in the drug unit. A new blow-fill-seal process which avoids the gas within the units of the medicament is described with reference to figure 11. This figure shows a vacuum approach to eliminate a volume on the liquid filled with gas. A drug container with an open end (101) produced by the conventional blow-fill-seal process was filled with medication (102). The container still has an opening (104) and a volume on the liquid (103). This medication container is placed in a chamber, which can be evacuated. The chamber (105) shown in Figure 11 has two halves and a seal (106) to form a gas-tight seal between those halves. When the camera is closed, a vacuum pump can be connected to the camera by a channel (109) that communicates with the interior of the camera (see figure 11 A). Fortunately, a strong vacuum is not necessary to avoid a volume on the liquid. It has been shown that pressures of less than 0.025 atmospheres are sufficient to avoid bubbles. After evacuation, the medication container is closed by narrowing the container opening as shown in Figure 11 B. Advantageously, the closure process can be performed by hot sealing tools (110) to form a hermetic seal to the air (111). When the container is sealed and the vacuum in the chamber is released, the chamber can be opened (Figure 11 C). The atmospheric pressure acts on the walls of the container so that the volume on the liquid is filled with liquid. Within this concept it has been shown that some liquids tend to foam when a vacuum is applied due to the gas physically absorbed in the liquid. Such foam formation is disadvantageous since the liquid is raised and moistens the closure area of the container. Therefore, it is advantageous to deaerate the liquid by evacuation, heating or other processes before filling it into the medicament unit. Within the present invention it is also contemplated to avoid the volume on the liquid by the following processes: - Before sealing, the volume on the liquid of the drug unit is filled with carbon dioxide gas. After sealing, carbon dioxide is easily absorbed by the liquid. - The volume on the liquid is filled with gas from substances that boil between 35 and 85 degrees Celsius.

After the sealing process, these gases condense and the volume on the free liquid vanishes. Particularly useful substances are ethanol and ethyl ether. - The volume on the liquid is filled with water vapor which condenses after the sealing process. - The sealing process is done in an inert gas atmosphere such as helium, methane or nitrogen. Small molecules that are easily propagated through the material of the drug container are preferred. After closing the container in the inert gas atmosphere, the container is introduced in a vacuum to remove the volume gas on the liquid by diffusion.

The present invention also addresses two concepts for the units of the medicament and the handling of the units which are particularly suitable for hypodermic injections. The injection system with adjustable injection pressure: An advantageous embodiment of the present invention is directed to a regulation of the pressure of the liquid jet. One measure to bring the pressure inside the explosion chamber in a suitable range is to adapt the amount of explosive and the free volume of the chamber which surrounds the first compressible container with each other. The chamber surrounding the first compressible container will be called the explosion chamber in the following. The pressure created in the explosion chamber depends on the amount of gas generated by the combustion of the explosive and the volume of the explosion chamber comprising the previous volume of the explosive and the free volume surrounding the first compressible vessel. The pressure applied to the first compressible container also depends on the temperature of the combustion gas which depends on a number of variables such as the type of explosive, explosion speed and so on. It has further been shown that it is advantageous to provide a gas outlet opening within the second container so that the combustion chamber communicates by means of this gas outlet opening with a free, adjustable volume. By adjusting this free volume, the user can adjust the pressure of the liquid jet to their own specific needs. The free, adjustable volume can be employed by a piston that moves in a cylinder and means to fix the piston in a specific position inside the cylinder. This modality will be described in more detail with reference to a figure that shows the concept of free volume. Within the free volume, adjustable concept, it is preferred to employ a filter means which prevents the particles of the gas generator from escaping from the explosion chamber in the free, adjustable volume. In addition, it is claimed that the modalities comprise two free volumes which are connected to each other. At least one of those two volumes is adjustable. An injection system of the invention further consists of an activatable gas generator. Possible gas generators are, for example, explosive substances such as gunpowder or black powder, nitrocellulose, pentaerythritnetetranitrate and the like. Of particular advantage are explosive substances that do not contain heavy metals such as lead or mercury, thereby avoiding environmental contamination because such substances with the explosion are degraded almost completely to carbon dioxide, nitrogen and water. Nitrocellulose, an impellent which is preferred by the present invention, produces substantial quantities of non-condensable gases, but not solid salt residues. Other impellers produce water vapor, which is condensable, and salt residues. The exposure or the kinetics of combustion can be controlled by the selection of the explosive substance and its geometric shape. In the context of the present invention it is advantageous when the explosive substance is not burned in an explosive manner, ie the pressure wave generated by the combustion has a speed lower than the speed of sound. It is particularly favorable when the total combustion of the explosive substance is in the time period of 10 to 20 msec. To achieve this, the explosive substance usually compresses very well to slow the progression of the glow zone. An additional factor which influences the kinetics of the increase in pressure is the size of the hole in the second container, which is filled with gas or air before the activation of the gas generator. The larger the space for gas, the slower the increase in pressure. Other devices can serve as gas generators, which are suitable for the pressure increase in the second vessel. Such a device can be, for example, an additional container with extremely compressed gas or gas that was liquified under pressure (such as, for example, C0 in a pressure vessel). The compressed gas which can be filled at the site, as is known for example in the case of C02 cartridges for siphons or the gas can be compressed by the user himself as is the case in commercially available hypodermic injection systems. In the present invention a concept can be used where a spring or spring is pressed by the user, which is forced against the pistons of a cylinder and compresses the gas in the cylinder. In this embodiment, the second container of the system of the invention can be formed as a cylinder in which a piston introduces energy by a spring or spring. The generation of pressure can be controlled by the release of the spring or spring. In systems that operate using compressed gas filled at the site, release can occur for example by piercing a seal in the pressurized * container. Such a process is also used for example in S02 siphons in which a C02 container is screwed into a long, thin hollow needle whereby in doing so a metal sheet is broken in the C02 container allowing the gas to flow. C02 flows through the hollow needle. However, systems driven with C02 without pressure transformation are not generally suitable within the present invention. But concepts are known to multiply the pressure for example with a large piston driven with pressure of C02 that is connected to a small piston that generates a higher pressure. In addition, the generation of gas can result from the rapid evaporation of a liquid for example through the use of u? electric heating spiral or electrical degradation (electrolysis) of a substance (usually a liquid) to a gas. An example of the last process is the electrolysis of an aqueous solution that produces gaseous products, usually hydrogen and oxygen. In addition, chemical processes can be used for the generation of gas, for example the reaction of fine or pure aluminum with a sodium hydroxide solution, whereby hydrogen is liberated. A hypodermic injection system has an exit orifice, through which fluid can escape from the medication unit. Preferably, the outlet orifice which is part of the medicament unit serves as a nozzle through which a stream of liquid / jet can be injected directly through the skin. There are also possible embodiments in which the outlet orifice leads into a nozzle, through which the liquid is expelled. This is possible, for example, when the medicament unit and its second region in which the outlet orifice is located is forced against a unit in which the nozzle is located such that the outlet orifice and the nozzle create a continuous channel . However, it is preferred to employ medicament containers that are directly in fluid communication with a nozzle. The injection of the liquid with the system of the invention can occur by means of an exit orifice or by means of a nozzle. The term "nozzle" simply implies that the channel through which the liquid leaves the first container has a shape which, by virtue of its geometry, can control the flow of the liquid. Penetration of the liquid to the deeper tissue layers can be achieved by focusing the jet, and the generation of a diffuse jet results in an injection reaching higher tissue layers. However, the depth of the penetration can be controlled by the pressure of the jet and the diameter of the hole. The larger jets penetrate deeper at a given pressure, since they remain coherent longer before disintegration. It has been found to be of importance that the nozzle or outlet hole be placed close to the surface of the skin. If the distance is very large, the moment of the liquid decreases and the jet can not penetrate the skin. As long as the liquid jet is focused by the nozzle or outlet orifice, a distance of several millimeters between the surface of the skin and the outlet orifice can not be tolerated. In cases in which the liquid leads to undesirable irritation of the surrounding tissue at higher concentrations, two or more outlet orifices can be provided instead of just one orifice, through which the liquid to be injected can pass. Such a medium achieves the distribution of the liquid over a larger area of tissue and the local concentrations can be maintained at a lower level. Devices known in the prior art, which operate using a steel spring or spring or a compressed gas, have the disadvantage that the pressure which can be generated by such means is relatively low and as such nozzles having a diameter between 130 and 200 μm. In the preferred embodiment of the invention which makes use of explosive substances, in contrast much higher pressures can be generated such that nozzles with a diameter of less than 130 μm can be used for those immediate purposes. The nozzles or outlet holes that have a diameter of between 80 μm and 130 μm are favorable because very efficient injections can be made using nozzles in this size range. Particularly preferred are the nozzle sizes in the range of 80 to 100 μm. A particular advantage of this invention is that the injection system can be devised in a very compact and user friendly manner. This is on the one hand due to the fact that when explosive substances are used as a gas generator, the space required for the gas generator is very small and also the means for activating the gas generator can be very simple in design. In addition, it is possible to use the system of the invention to make disposable, commercially available modules, which consist of a drug unit, a surrounding container (which provides an explosion chamber) as well as a gas generator located within the container surrounding. Such a disposable module has to be inserted only in a handling device, which contains an activator for the gas generator. It is still possible to provide a disposable injection system which also comprises a device for the activation of a gas generator. Such a system can be achieved, for example, by using an explosive substance as a generator, whereby the explosive substance is exploded by the action of a flame igniter. Advantageously, activation of the gas generator can occur using a piezo igniter as is known, for example, for fire lighters. The previously established advantage, specifically the possibility of making disposable, commercially available modules is particularly justified due to the fact that the gas generator can be integrated into the module while in the systems described in the prior art the gas generator has to be integrated in the management unit. Particularly suitable as gas generators for such a disposable module are those in which the energy is stored in a potential form and does not have to be generated by the user himself, for example by virtue of his spring or spring pressure. Particularly preferred are explosive substances as gas generators. The present invention additionally facilitates the possibility of providing systems that are composed of two or more components. In such systems, the drug unit is inserted into a surrounding container and the order is closed in such a way that the gas generated in the surrounding container can not escape but preferably exerts pressure on the compressible region of the medication unit. In such embodiment of the invention, a surrounding container is usually part of a handling unit and the handling unit has a device with which the arrangement of a surrounding container and the medication unit can be connected together in such a way that the gas can not escape from the container. surrounding vessel in the course of the injection process. A surrounding container may consist of a hollow cylinder in such an embodiment of the invention, such that the front face (transverse end) is opened and through which the medication unit may be inserted. The cylinder is provided with a closure device in the region of the open front face, which is opened when the drug unit is employed and can then be closed in such a manner that the drug unit is preferably sealed in the second region. In such two-component embodiments of the injection system, various types of gas generators can be employed as described above. These are for example explosive capsules which are placed in the surrounding container prior to injection or gas generators can be used which operate using cylinders which in turn are mechanically driven by a spring or compressed spring. The invention is illustrated in more detail by the following figures: Figure 1: Injection system before activation of the gas generator Figure 2: Injection system after activation of the gas generator Figure 3: Injection system with a drug unit that has a membrane and a surrounding container (before the injection procedure) Figure 4: As in Figure 3 after the injection process Figure 5: Module of a drug unit and a gas generator Figure 6: Injection system in which a module according to Figure 5 is inserted into a surrounding container Figure 7: Injection system with free volume, adjustable Figure 7a: Concept of free, adjustable, improved volume Figure Pressure curves for several free volumes Figure 9: Kinetics of the injection for several free volumes Figure 10: Injection system with gas leaks Figure 11: Process of blowing, filling, sealing under vacuum Figure 12: Unit of type A medication Figure 13: Type B management unit Figure 14: Unit of type B medication Figures 1 and 2 show a first embodiment of the injection system according to the invention before and after activation of the gas generator.

In Figure 1 can be recognized a primary compressible container (1) in which a liquid is located. The first container is surrounded by a surrounding container (2) in which the gas generator (5) is located in the form of an explosive material. In addition, a hollow space is located between the primary container and the surrounding container which can be filled with gas or evacuated. Charging this area with gas is advantageous when the velocity of the pressure increase in the surrounding vessel must be reduced while the evacuation of the intermediate space is of advantage when an accentuated elevation of pressure is desired. In most cases it is appropriate to allow air in the atmospheric pressure to fill the intermediate space during the production process. The first container (medicament unit) has a channel at its front end, which leads to an outlet orifice (4). The channel is located in the region in which the second region of the first container is located. In this region, the first container is preferably built relatively strong, to enable safe assembly and in particular, a gas-tight assembly. At its rear end (the first region), the container is designed in a compressible manner. This first region is preferably made of an elastic plastic similar to, for example, polyethylene or polypropylene. The first container is manufactured in a manner analogous to disposable bottles for eye drops. Similarly, they also have a region which can be compressed by the user for the discharge of eye drops and an exit hole which can be carried to the eye. Therefore, the production of the first container of the invention is known to those skilled in the art from the field of disposable ampoules for eye drops.

Despite the high pressures acting on the flexible region of the first container, no special provisions have to be made to increase its mechanical stability. This is due to the fact that the development pressure is distributed relatively evenly on the total coating of the first container such that no cutting forces arise which would give rise to the mechanical deformation. As illustrated in Figure 1, it is of advantage when the first container is, where possible, completely filled with liquid. This is preferred due to the fact that on the one hand, a decrease in pressure can occur due to the compressibility of the gas in air bubbles and on the other hand there is a danger that such gas can be injected into the fabric. However, it has been discovered that the second named hazard is of little significance because the impulse which can be transferred through the air is small due to its low density and therefore, penetration of the surface of the skin can not normally occur. In Figure 1, a closure (6) is illustrated, which seals the outlet orifice (4) before use of the system. This closure can be advantageously connected to the second region of the medicament unit by means of a predetermined breaking point such that the removal of the closure can occur by rupture (as illustrated) or by rotation (twisting). Such closures are also known from disposable ampoules for eye drops. Such containers are preferably molded for injection as open containers in which the liquid is filled. The closure is subsequently fixed or melted in such a way that a twisting of the part of the projecting material is possible. In this invention it is of advantage when the outlet orifice has contours and in particular the shape of the outlet channel is predetermined and is not influenced by the twisting as in the case of eye drop ampoules. In the case of ampoules for eye drops the twisting of the closure creates the outlet channel so that the shape and the inner diameter of the exit orifice is dependent on the twisting / rotation procedure. In the preferred containers according to the invention, the outlet channel and the exit orifice are in contrast already formed during the production process (which is usually an injection molding process) and the predetermined breaking point, which it mounts the closure to the container, it is located outside the direct vicinity of the outlet orifice such that during twisting the deformation of the outlet orifice does not occur. A particular advantage of the device shown in Figure 1 is that hole diameters down to 130 or better below 100 μm can be used. Such small holes reduce pain during injection. In Figure 1, it can also be recognized how the drug unit (1) and the surrounding container (2) are connected to each other. In the illustrated case, a sealing material (13) is located between the containers which develops the second region of the medication unit (1) and seals the surrounding container of its environment. The ordering of the first and second containers is located in a stabilization coating (7) that surrounds the surrounding container and which is closed using a screw cap (8). The screw cap also serves to secure the seal (13). However, other types of closures and other mechanisms can be used to fix the closure in the second container. Figure 1 shows a disposable module which comprises the unit of the drug (1) and the surrounding container (2) in which it is. locate the gas generator (5). For repeated injections, the user only has to replace a disposable module used by an unused one. It can be recognized from Figure 2, how the first flexible region of the drug unit is compressed by the gas released into the surrounding container (10) and expels a jet of liquid (12). Furthermore, in Figure 1 and 2 there is illustrated a device for activating the gas generator (5) which exhibits electrical contacts (9) leading from the surrounding vessel to the outside, between which a hot wire is located inside the vessel. surrounding vessel. When an electric current flows through the hot wire, the hot wire is excited at such a temperature that the explosive substance that serves as a gas generator is ignited (5). To perform an injection procedure with an injection system according to the invention, the device illustrated in Figure 1 and Figure 2 including the outlet orifice is placed on the skin and then the gas generator is activated. A second embodiment of the injection system of the invention is illustrated in Figures 3 and 4. These figures show a disposable module which comprises a unit of the medicament., a surrounding container and a gas generator.

Between the container (20) and the explosion chamber (21), a primary membrane (23) is located, which is moved by activating the gas generator from the position illustrated in Figure 3 to the position illustrated in the Figure 4. The membrane (23) can be made of a plastic such as polyethylene or also of a sheet of metal such as aluminum. In this embodiment of the injection system according to the invention, the components that can slide together and the associated sealing problems can be avoided.

In addition, in Figures 3 and 4, a secondary membrane that can be used to improve is illustrated. After activation of the gas generator, the first membrane (23) moves in the direction of the nozzle (25) and compresses the liquid contained in the first container (20), whereby the secondary membrane (24) is forced in the direction of the nozzle (25) and thereby pierced by a roe needle (33) which is directed to the direction of the first container. After perforation of the secondary membrane, the liquid located in the first container is forced through the nozzle. Figures 3 and 4 also show a ventilation hole (31) which allows air to escape from the space (32) when the secondary membrane (24) is forced against the hollow needle (33). The ventilation hole (31) comprises an annular space around the hollow needle which is connected to perforations in a second molded part (27) and a clamp (28). The ventilation hole (31) prevents the pressure in the space (32) from rising when the secondary membrane moves. The ventilation hole (31) is advantageous for improving the seal between the secondary membrane (24) and hollow needle (33) after drilling. The embodiment illustrated in Figures 3 and 4 has a first and second lining (26,27) which are held together by a bracket (28). The primary and secondary membranes are clamped between the outer coatings. The first preformed part (26) has a recess in which a covering (29) made of an electrical insulation material (29) is located which is penetrated by an electrical contact (30). The first liner (26) is preferably manufactured from an electrically conductive material such that the application of an electrical potential between the first liner (26) and the electrical contact (30) gives rise to the ignition of an explosive substance contained in the Explosion chamber (21). If the explosive substance is selected appropriately, hot wire or the like can be provided. Such explosive substances usually contain a finely divided metal such as, for example, aluminum, by virtue of which a certain electrical conductivity of the explosive substance is achieved. Figure 5 illustrates a disposable unit for an injection system in which the medicament unit and the second container are separated from each other. In Figure 5 there is illustrated one embodiment of a medicament unit (40) whose outlet orifice is closed by a knob (41). In addition, a gas generator (42) is illustrated in the form of an explosive substance which is located outside but connected to the drug unit (40). In a rear view of the module also illustrated, the electrical contacts (43) with which the gas generator (42) can be ignited are recognized. The unit of the drug of Figure 5 has a unique topology in which the gas generator is connected, but outside the drug unit. This type of medication unit minimizes the amount of material that is necessary to produce the medication unit. This ordering can be manufactured in a blown, fill, seal process which is further described below or an injection molding process. With both processes, the drug unit that has the gas generator attached to it can be formed. The connecting piece of the material can be formed of the same material as used for the medicine unit and the material enclosing the gas generator. This further simplifies the manufacturing process of the handling unit shown in Figure 5. Figure 6 illustrates a handling unit into which the module illustrated in Figure 5 can be inserted. For this purpose, the operating unit (45) has a hollow space inside it into which the module illustrated in Figure 5 can be inserted. For this purpose, the sliding lid (46) is driven first of all to the side so that it is opens the hollow space in the operating unit. The module, according to Figure 5, is inserted and the sliding lid is closed which results in a sealing of the first container against the second container. The operating unit has electrical contacts in its interior which can be connected to the electrical contacts (43) of the module and by means of which the ignition can take place using a battery. After use, the first spent container of the operating unit (45) can be removed by opening the sliding lid (46) and if necessary it can be replaced by a new module.

Figure 7 shows an injection system (50) with a free volume, adjustable to regulate the pressure of the liquid injection jet. Within this system a unit of the drug (51) is shown which will be described in more detail in the following. This unit of the medicament (51) has a reservoir for the liquid medicament (52) and a nozzle (53) to expel a jet of liquid from the medicament. The modality shown in Figure 7 serves mainly to explain the concept of free, adjustable volume and is not limited to a specific type of drug unit. The medication unit (51) is seated in an inner liner (54) which is made of a material that can withstand the pressures generated within the explosion chamber (80). Suitable materials for this interior coating are hard plastics such as polymethyl methacrylate and polycarbonates. The inner lining (54) can also be made of metals such as steel or bronze. The inner lining (54) can also be made of flexible materials such as polyethylene or polypropylene if the medicine unit is surrounded by a rigid receptacle during the ignition of the explosive. The inner lining is surrounded by an outer coating (55). The outer lining (55) can be made from the same materials as the inner lining. The two coatings serve to keep the drug unit in the middle so that an explosion chamber (80) is formed in which at least one reservoir must be provided. An explosive or impeller (56) is also located within the inner lining which can be ignited by a hot wire (57) or the like. Figure 7 shows no electrical contact within the body of the device (69) to connect the electrical power to the hot wire (57) since this was previously described and is also known in the prior art for making such contacts. Figure 7 describes a disposable module which is formed by the drug unit (51), the liners (54,55) and the gas generator (57). The outer sheath (55) shown in Figure 7 has two 0-ring seals (58, 59) which seal the outer sheath against the body of the device (69). Optionally, the system shown in Figure 7 has - a notch for the gas (61) disposed in the body of the device (69) and annularly surrounding the outer skin. In a preferred embodiment, the medicament unit has a tubular shape and the body of the device (69) has a tubular recess for receiving the medication unit.

Therefore, a user of the injection system can place the medication unit in the hole in any rotational orientation. The unit of the medicament shown has a gas outlet opening (60) with a cross section of 2 to 5 mm. Typically, the gas outlet opening (60) is in the form of a cylindrical bore, it is also possible to employ the drug units with two or more gas parts that are typically arranged in a circle at a common distance from the bottom of the unit of the medication. The notch for the gas (61) ensures that there is a free passage from the explosion chamber (80) to the free volume (64) with respect to the rotational orientation of the drug unit within the body of the device (69). Analogously, there is a possible mode where the notch for the gas (61) is achieved as a notch in the outer circumference of the drug unit. In such an embodiment there is no need for a notch for the gas in the body of the device (69) since the notch in the medicament unit easily guarantees a passage for the free gas. Figure 7 also shows how the injection unit is held within the body of the device (69). The injection unit is placed within a recess in the body of the device (69) and a cover (62) is closed over the injection unit. The cover (62) comprises a gap through which the nozzle (53) of the medication unit (51) projects. The cover (62) is maintained within the closed position by a hook (63). For the removal of the injection unit, the hook is opened and the cover is rotated around the joint (81). The injection unit can now be taken outside the body of the device (69). An important aspect of the embodiment shown in Figure 7 is the gas outlet opening (60) which connects the explosion chamber (80) with a free, adjustable volume (64). The gas outlet opening (60) traverses both the inner liner and the outer liner. Within the present invention there are also contemplated embodiments that do not have only an inner lining that holds the medication unit (51). In these embodiments, the gas outlet opening (60) would not traverse the coating or the present coating. Advantageously, the gas outlet opening can be provided with a filter means as explained later for Figure 7a. Figure 7 further shows a free, adjustable volume (64) in which the gases from the explosion chamber (80) can be expanded. The free volume (64) can be adjusted by moving a piston (65) within a free volume chamber by rotating a knob (67). The knob (67) is attached to a screw (68) which rotates in a nut of the body of the device (69). With respect to the high pressures within the free volume (64), the piston and the screw have to be made of stable materials such as a metal. To prevent a leakage of gas from the free, adjustable volume (64) into the remaining chamber, the piston (65) must be sealed against the cylinder (82). It is advantageous if the free volume (64) can be varied between zero and a volume of four times the volume of the explosion chamber (80). In particular, it is advantageous if the free volume (64) can be varied between zero and a volume of twice the volume of the explosion chamber. Figure 7 further shows a vent hole (70) which allows gases to escape slowly from the free, adjustable volume (64). The ventilation hole (70) must be dimensioned such that the pressure in the first milliseconds after the ignition is only slightly reduced by the escape of gas through the ventilation hole. On the other hand, the ventilation hole has to ensure that the pressure inside the injection systems is balanced with the ambient pressure when the user opens the device. Particularly, the well-fitting ventilation hole diameters have been found in the range of 0.01 to 0.5 mm. Figure 7a shows an improvement of the free volume, adjustable concept. The explosion chamber (80) and the drug unit (51) are shown only schematically. In figure 7a a filter means (83) is shown. The filter medium (83) is discarded between the explosion chamber (80) and the free, adjustable volume. The filter medium (83) has holes of approximately 0.5 to 1 mm in diameter.

Depending on the particular needs there may be two to ten of the holes. The free, total diameter of all holes should provide a flow area equivalent to an individual hole in the range of 2 to 8 mm. The filter medium has two functions. In the first, the filter medium prevents the larger particles of the explosive from escaping from the explosion chamber. This keeps the free, adjustable volume clean and ensures that the total amount of the explosive burns. The latter is very important to make the explosion process reproducible so that the pressure curves are predictable. If the particles of more than 1 mm escaped from the explosion chamber, those particles would not burn completely, which results in a loss of gas to be produced by the explosion process. The other function of the filter medium (83) is a flow resistance for the gas escaping from the explosion chamber. The filter medium can be made of materials such as steel, hard alloys and ceramics. It is still possible to produce the body of the device (69) with a wall that remains between the explosion chamber and the free, adjustable volume, the wall that is provided with holes later. In addition, it is preferred to employ filter media which are porous and have holes in the desired range. Figure 7a further shows a free, adjustable volume (88) which is adjusted not only by a flat piston as shown in figure 7, but with a tapered piston (84) and a correspondingly formed recess (89). The gas in the explosion chamber (80) has to pass the gap (89). With such a tapered piston (84) and a corresponding recess (89) it is possible to vary the small volumes of the volume adjusted smoothly.

And it is further possible to provide a non-linear volume increase over a linear travel distance of the piston (84). This may be of importance in providing easy-to-adjust equipment for depth of penetration and / or skin type. The tapered portion of the piston may have a spherical, paraboloid or inverse paraboloid shape as shown in Figure 7a. A further improvement that figure 7a shows is the combination of two free volumes (88, 85). The first free volume (88) can be adjusted by the piston (84). The second free volume (85) can be fixed or adjusted by a second piston (86). The first and the second free volume are connected to each other by a channel (87). The second free volume (85) must be capable of adjusting the largest part of the free, total volume.

This adjustment is usually made by the manufacturer. Fine adjustment of the free, total volume is made by the user by means of the piston (84) in the manner as described with reference to figure 7. It is preferred to employ a piston which has a tapered portion as described above as well as also a cylindrical portion. The location of the channel (87) can be selected so that the channel is closed by the cylindrical portion when the free, adjustable volume is minimal and the channel that is opened continuously when the free, adjustable volume (88) is increased. This arrangement provides good control of the pressure curve since not only the free volume can be adjusted but also the filling speed of this volume can be controlled by virtue of the adjustable flow resistance. Figure 8 shows a pressure on the time diagram for several free volumes. The figures were generated by using a device as shown in figure 7 with an explosion chamber (80) of 1 cm3 and an explosive volume of 0.7 cm3. The explosive used by these experiments was nitrocellulose. Figure 8 shows in the ordinate the pressure inside the explosion chamber (80) in pascal and the time is shown in the abscissa in milliseconds. The highest pressure inside the explosion chamber is obtained with a free volume of zero (see curve designated Pj, 0). The other curves were obtained with a free volume (64) of 0.5 ccm (p-¡, l); 1.0 cm3 (pj2); 1-5 cm3 (PJ3) and 2.0 cm3 (pj4). The figures show that the pressure curve for the injection can be easily controlled by using a free, adjustable volume. Figure 9 shows how fast the liquid medication should be expelled from the reservoir using the free volumes mentioned above. In the ordinate the remaining volume is given in the deposit and in the abscissa the time is given in milliseconds. Within these experiments, an initial liquid volume of 0.24 ccm was used. The figure shows that with a free volume of zero (lower curve) the volume is almost totally expelled within 45 ms. With a free volume of 2.0 ccm (higher curve) it is possible to significantly decrease the ejection speed. The other curves shown in figure 9 belong to 1.5 ccm, 1.0 ccm and 0.5 ccm of free volume from the top to the bottom. Figure 10 shows an additional system comprising an injection unit and a unit for supporting the injection unit. The injection unit comprises a unit of the medicament (51) which is maintained by the arrangement of an inner lining (54) and an outer lining (55). The injection unit is placed in a body of the device (90) and secured within the body of the device by a cover (91) which is screwed into the body of the device. The arrangement shown in Figure 10 does not have a free, adjustable volume to control the injection pressure. In contrast, the device of Figure 10 uses a ventilation concept to vent the air from the explosion chamber (92). After the explosive (93) has been ignited, the gas pressure can escape from the explosion chamber (92) by a leak between the medicament unit (51) and the inner liner (54). The gas then finds a path through the space between the inner and outer sheath and then between the outer sheath and the body of the device (90). The gas is then contained by a 0-ring seal (92) which seals the outer skin (55) and the body of the device (90) to each other. An additional route that the gas can take from the explosion chamber (92) is through a leak between the inner lining (54) and the medication unit (51) then an opening passes between the medicament unit and the outer lining and finally leaves the system in a controlled way through a weak seal (93) between the drug unit (51) and the outer coating. By adapting the resistance to system flow to the combustion gases, the pressure on the time curve can be adapted to provide appropriate injections. The embodiment shown in Fig. 10 is particularly well suited for providing single shot injection systems, which can be completely discarded after use. The disposable module does not only comprise the drug unit, the surrounding chamber and the gas generator but also a stabilization coating which gives mechanical stability to the surrounding chamber after the ignition. It is possible to integrate an activator for the gas generator in this unit so that the user is provided with an independent injection system. Figure 12 shows a longitudinal section through a novel type of drug unit (120) for hypodermic injections. The liquid medication (121) is enclosed in a compressible container (122) (volume shown: 0.2 cm3). The container wall surrounds the medicament as well as a nozzle unit (123). The nozzle unit is a specific embodiment of the second region of the medicament unit, while the compressible portion below the nozzle unit is a specific modality of the first region. The medicine unit has rotational symmetry in its lower region (compressible container and nozzle unit) which simplifies insertion into a handling unit. The shape of the compressible container 122 is particularly useful. The compressible container has a part of the flat bottom (126) connected by a part of the flare wall (127) to a part of the tapered wall (128). When pressure is applied to those parts of the wall (126, 127, 128), the nozzles of the container and the liquid medicament are expelled through the nozzle unit (123). The specific shape of the compressible container ensures a total expulsion of the medicament, which is desirable to make possible a precise dosage of the medicament to a patient. However, the form shown in Figure 12 is only for exemplary reasons and not to limit the claimed invention. The compressible container is preferably made of polyethylene, polypropylene or PVC because of its flexible characteristics and its inert nature against common medicated fluids. It is valuable to say that it is a particular improvement over the prior art to employ, even for the mouthpiece, materials that do not affect almost every medication. In addition, the medication is completely wrapped in sterile materials and can be opened in a way that fluid contamination does not occur. Figure 12 further shows the nozzle unit (123) having a channel (124) communicating with the compressible container (122) at its first end and leading into a nozzle (125) at its second end. The outer shape of the nozzle unit is adapted to securely hold the medication unit within a handling unit. The nozzle unit has an inner region mainly in the form of a cylinder through which the channel runs and an integral ring portion surrounding the inner part. It is of particular advantage that the wrapping wall (131) forming the compressible container extends over the nozzle unit and completely envelops the nozzle unit. This will become clearer when the production process of the drug unit is described later. It is particularly preferred to use the same materials for the nozzle unit and the wrapping wall because in this case the two articles are at least partially melted together which leads to a fluid-tight connection. The fusion process is usually achieved by the cold flow behavior of these materials. The medication unit (120) is closed by an appendix (130) which is connected to the wrapping wall (131) by means of a predetermined breaking region (132). Alternatively, the appendix (130) can be connected directly to the nozzle part (123) over a predetermined breaking region. Figure 12 further shows a thin, optional plate (129) covering the outlet of the nozzle. That plate is removed when the appendage (130) is removed from the medication unit. The thin plate may be a metal foil or the like which prevents leakage of medication from the medication container. This effect can also be achieved by an integral, thin wall that closes the outlet end of the nozzle. However, the thin plate or the integral, thin wall are only optional. It has been shown that the leakage is only small or totally absent when the sizes of the nozzle used in the present invention are used. Figures 12B and 12C show perspective drawings of the drug unit (120). It can be observed from these figures that the region of the compressible container and the nozzle unit have rotational symmetry while the appendix (130) is generally flat to facilitate handling. A nozzle that is used in a drug unit for hypodermic injections preferably has an internal contour of rotational symmetry and an exponential slope. An exponential slope can significantly reduce the radial velocity gradient of the liquid inside the nozzle. An exponentially sloping nozzle is therefore of particular advantage when the medicament contains substances which are sensitive to the cutting forces. This is the case for molecules such as nucleic acids, proteins, etc. The preferred nozzle shapes are given by the following equation.

T = a- exp (b • X) where X = x or X = c + dx + ex2 + fx3 with X as a linear coordinate that starts with X = 0 at the outlet of the nozzle and r as radius of the nozzle. a, b, c, d, e and f are coefficients that are selected according to the particular conditions. The coefficient determines the diameter of the nozzle at the outlet and is an important factor that determines the speed of the ejected liquid. Preferably, it is in the range of 0.04 to 0.08 mm. The other coefficients are dependent on the length of the nozzle, which in turn depends mainly on manufacturing requirements. It is particularly preferred to have an exponential function with a point of inflection. Therefore, such a function changes its inflection direction. The coefficient e can be zero, while it is preferred for the other coefficients that is unequal to zero. A useful, particular set of coefficients is: c = -2, 8615 d = 0.7322 e = 0.0 f = 0.0038 When the exponential slope is problematic to produce, a polygon that approximates an exponential slope can be used. A useful, particular mouthpiece has three sections: - Section: An entry section to the end of the mouthpiece that communicates with the liquid medication. The inlet section has a rounded shape so that a change in pressure in this region is reduced as much as possible. - 2nd section: A section of the exponential slope as described above which is connected continuously to the input section and the 3rd section. - 3rd section: An exit section which ends at the exit surface from which the medication leaves the medication unit. In the outlet region, the nozzle should not be widened as this can lead to disintegration of the liquid jet. Therefore, an acute edge between the nozzle and the exit surface is preferred in the exit section. As already mentioned, plastics such as PVC, polyethylene and polypropylene are preferred for the nozzle unit. Due to the high pressure during injection, these soft materials are significantly deformed. A first approach to meet this problem is to use a smaller nozzle as necessary and allow the nozzle to expand during injection. Typical pressures during injection are in the range of 300-800 atmospheres. Provided with a polyethylene nozzle with a diameter of 0.1 mm, a pressure of 1000 bar would lead to a widening of approximately 50% of the diameter of the original nozzle. A second approach is to surround the nozzle or at least the outlet section with a harder material. The nozzle can be enclosed by a metal, ceramic or harder plastic ring such as polymethyl methacrylate or the like. The surrounding materials do not make contact with the drug and therefore no disadvantageous interactions can occur. It has been shown that it is particularly useful to contract or reduce the surrounding material in the nozzle. However, if the nozzle has a thick wall made of a soft plastic, the diameter of the nozzle can be expanded even if it is surrounded by a harder material. Therefore, it is advantageous to keep the nozzle wall below 1 mm. The surrounding material can be heated to expand, place the nozzle and cool to enclose the nozzle. Vice versa, the nozzle can be cooled quickly and a ring of hard material is placed around the nozzle so that an airtight fit is achieved during the nozzle heating process. Other methods for applying a ring of hard material onto the nozzle are press fit or folding. The production of a unit of the medicament as shown in Figure 12 comprises the following steps: a nozzle unit is formed, for example in an injection molding process an open-ended container is formed (for example in a process blow-fill-seal) - liquid medication is introduced into the container - the nozzle unit is inserted into the container through the open end - the medicament container is formed around the nozzle unit so that the wall encloses the nozzle unit and a predetermined breaking section and an appendix are formed. The medicine unit of type A described above can be used in a handling unit. Therefore, the drug unit is placed in an explosion chamber so that the compressible region (122) is located within the explosion chamber and the drug unit is held with its part of the ring of the nozzle unit ( 131). A gas generator can be placed inside the explosion chamber. Such a handling unit provides the user with all the disposable parts combined in a handling part which is of particular advantage. The type A medication container or a handling unit based thereon can be favorably employed within an injection system with a free volume, adjustable as further described below. The type B medication unit and the handling unit Figure 13 shows a type B handling unit (150) pressed with a corresponding type B medication unit (151). Figure 13 A is a cross-sectional plan view and Figure 13 B a perspective drawing of a cut-off handling unit. In this embodiment the medication container (151) is interposed between a first liner (152) and a second liner (153) which are fixed together. Within the embodiment shown, the second liner (153) has an extension portion that closely surrounds the bottom liner. However, other fixings of the coatings are jointly within the experience of an artisan in this field. The second coating also has a recess adapted to receive a unit of the medicament. The first liner (152) contains an explosive (154) which can be ignited and then creates pressure within the explosion chamber (155). The embodiment shown in Figure 13 does not have a wall for closing the explosion chamber against the environment because this operating unit is designed to be placed in the injection system which provides a closing wall. However, handling units where a closure wall belonging to the coating of the handling unit is present are also within the scope of this invention. The second liner has a needle (156) inserted therein which serves as a nozzle. The needle has a pointed tip at its first end facing the handling unit to pierce the medication container. The second end of the needle points away from the top coating so that it can be directed to the surface of the body where the injection is desired. The handling unit further has an appendage (157) connected to the second liner (153) by means of a predetermined breaking area (158). Within the appendix (157) a plate (159) covering the needle is located. This plate facilitates the production process of the handling unit. An important aspect of the invention is the medication unit of type B (151) which is shown in more detail in figure 14. Figure 14 A shows a cross-sectional view while figure 14B is a perspective view . The unit of the medicament (151) is made of a first segment (170) and a second segment (171) which are connected together so that a closed cavity must be formed to keep the liquid medication therein. The two segments are preferably made of plastic. Polyethylene and polypropylene are particularly advantageous due to their inert behavior against most types of medicine. The segments can be produced, for example, by injection molding. The two segments can be glued, soldiers or fused together. Welding and melting are preferred because the tails are not necessary that could adversely affect the medicament. Figure 14 shows a thickened portion (174) which surrounds the annulus between the drug cavity similar to a ring of Saturn. It has proven advantageous to use an additional amount of material in this region to ensure that the two segments can be easily welded together. The second segment (171) has a concave portion (173) in the region where the perforation of the drug unit occurs. The first segment (170) has a convex portion (172) which prevents the piercing of this segment by the needle. For reasons of clarity, Figure 14 also shows the needle (156) located below the second segment (171) which is pierced. When pressure is generated in the explosion chamber (155) this pressure acts in the first segment (170) deforming this portion so that pressure is generated within the medication container. Due to this pressure, the concave portion (173) of the second segment (171) flexes outwardly, makes contact with the needle (156) and is punctured. The pressure that is still acting on the first segment (170) deforms this segment until it is located closely on the inner wall of the second segment. However, the convex portion prevents perforation of the first segment. The convex portion can be covered by a membrane on its outer side which protects the convex portion against the combustion gases and the pressure. An additional aspect of the type B handling unit is that the top cover (153) has a gap which supports the first segment (170) so that this segment deforms only in the concave region.

List of reference numbers (1) first compressible container / medicine unit (2) surrounding vessel (3) liquid (4) exit hole (5) gas generator (6) closing (7) stabilization coating (8) screw cap (9) electrical contacts (10) gas (12) liquid jet (13; sealing material (20) reservoir: 2 i explosion chamber (23) primary membrane '24 secondary membrane: 25' nozzle (26; first coating '27' second coating (28; clamp (29) electrical insulation material oo: electrical contract; ventilation hole 32 space (33; hollow needle (4 o; medicine unit (4i; knob / closure leg '42 gas generator (43! electrical contact (45; operating unit 46 'sliding lid: 50' injection with free volume, adjustable (51 medication unit 52 'liquid medicament 53' nozzle (54 inner liner (55; outer lining (56; impeller / gas generator (57; seal hot wire (59; seal 60 'gas outlet opening (6i; notch; gas (62; cover 63 'hitch (64; free volume, adjustable (65; piston (66) seal (67; knob (68; screw (69; device body (7th vent hole (s; explosion chamber) 8i; articulation 82; cylinder (83; filter medium (84; tapered piston (85; second free volume, adjustable; second piston (87; channel first volume free, adjustable (89) hollow (90; body of the device; cover 92) explosion chamber (101) medicine container (102) liquid medication 103) volume on liquid 104) opening (105) camera (106) seal (107) vacuum current (108) empty (109) channel (110) heated narrowing tools (111) airtight seal ; 120) Type A medication unit (121) liquid medication (122) drug container / first compressible region (123) nozzle unit / second region (124) channel 125) nozzle (126) bottom of the medication container (127) part of the widening wall (128) part of the tapered wall (129) plate covering the outlet nozzle (130) appendix (131) wall material (132) predetermined breaking region (150) handling unit type B (151) medicine unit type B (152) first coating (153) second explosive coating (154) (155) explosion chamber (156) needle (157) appendix 158) predetermined breaking region (159) plate 170) first segment (171) second segment (172) convex portion 173) concave portion (174) ring wall It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following claims is claimed as property.

Claims (41)

1. A hypodermic injection system for fluids, characterized in that it comprises a unit of the medicament in which the liquid to be injected is stored and which has a first and a second region, the first region is compressible or flexible and the second region that has at least an orifice, an explosion chamber in which the medicament unit is located at least partially and a pressure generated within the explosion chamber deforming the first region of the medicament unit, an activatable gas generator, located within the explosion chamber that generates a pressure inside the explosion chamber when activated, an activation unit to activate the gas generator, wherein the explosion chamber has a gas outlet opening connected to a free volume chamber having a variable volume.

2. A hypodermic injection system according to claim 1, characterized in that the free volume chamber is formed by a housing in which a piston is movably located, the position of the piston within the housing defining the volume of the cylinder which It is accessible for the gas from the explosion chamber.

3. A hypodermic injection system according to claim 1, characterized in that the gas outlet opening has a cross section in the range of 2 to 5 mm.

4. A hypodermic injection system according to claim 1 or 2, characterized in that the volume of the free volume chamber can be varied between zero and a volume of four times the volume of the explosion chamber.

5. A hypodermic injection system according to claim 1 or 2, characterized in that the free volume chamber has a ventilation hole.

6. A hypodermic injection system according to claim 5, characterized in that the ventilation hole has a cross section, free from 0.01 to 0.5 mm.

7. A hypodermic injection system according to claim 1, characterized in that the system comprises a filter means located between the explosion chamber and the free volume chamber.

8. A hypodermic injection system according to claim 7, characterized in that the filter means has holes with a free diameter in the range of 0.5 to 1 mm.

9. A hypodermic injection system according to claim 7 or 8, characterized in that the free, total diameters of all the holes provide a flow area equivalent to an individual hole that is in the range of 2 to 8 mm.

10. A hypodermic injection system according to claim 1, characterized in that the free, adjustable volume is divided into a first and a second free volume which are connected by a channel.

11. A hypodermic injection system according to claim 9, characterized in that at least one of the first and second free volumes is adjustable.

12. A hypodermic injection system according to claim 11, characterized in that the first free volume is adjustable by a user and the second free volume has been adjusted by the manufacturer.

13. A hypodermic injection system according to claim 1, characterized in that the free volume chamber is formed by a housing in which a tapered piston moves and the housing that is formed correspondingly to adjust with the piston when the free volume is minimal .

14. A hypodermic injection system according to claim 13, characterized in that the housing has a channel which connects the first free volume with a second free volume.

15. A hypodermic injection system according to claim 14, characterized in that the tapered piston has a tapered portion as well as a cylindrical portion and the channel that is located within the housing that closes when the first free volume is minimal and opens continuously when the first free volume increases.

16. A unit of the medicament for hypodermic injections, characterized in that it essentially comprises a first region which is compressible or flexible, - a second region having at least one hole, liquid medicament contained within the unit of the medicament and - a closure for closing at least one orifice wherein the unit of the medicament is made of PVC or polyethylene, polypropylene or mixtures thereof.

17. A unit of the medicament according to claim 16, characterized in that the closure is connected to the first or second region with a predetermined breaking point.

18. A unit of the medicament according to claim 16, characterized in that the second region and the first region are separate pieces and the second region is wrapped by the first region.

19. A disposable module for transdermal injections, characterized in that it comprises a first region which is compressible or flexible, a second region having at least one orifice, - liquid medicament, a closure for closing at least one orifice, a surrounding chamber in which the less a part of the first region is enclosed such that a pressure generated within the surrounding chamber deforms the first region and the liquid medicament is expelled through at least one orifice, wherein the first and second regions are made of PVC or polyethylene, polypropylene or mixtures thereof.

20. A process for producing units of the medicament useful for hypodermic injections, characterized in that it comprises the steps: forming a nozzle unit forming an open end container introducing liquid medicament into the container introducing the nozzle unit into the container through the open end - close the open end to form the medicament container around the nozzle unit.

21. A process according to claim 20, characterized in that the nozzle unit is made in an injection molding process.

22. A process according to claim 20, characterized in that in the process of closing the open end an appendix and a predetermined breaking region is formed between the appendix and the drug unit.

23. A process according to claim 20 or 22, characterized in that the closing process is done while the drug container is in a vacuum.

24. A unit of the medicament for transdermal injections, characterized in that a first region which is compressible or flexible and which is formed by a wall material, a second region having at least one hole, - liquid medicament - a closure for closing at least one orifice, wherein the first and second 'regions are made of separate pieces.

25. A unit of the medicament according to claim 24, characterized in that the wall material forming the first region surrounds the second region.

26. A unit of the medicament according to claim 25 or 26, characterized in that the wall material is integrally connected to an appendix by means of a predetermined breaking region.

27. A unit of the medicament according to claim 24, characterized in that the first region has a substantially flat bottom and a tapered wall portion connected to the bottom by means of a widening wall portion.

28. A unit of the medicament according to claim 24, characterized in that the second region comprises a rotational and exponential symmetric slope nozzle.

29. A unit of the medicament according to claim 28, characterized in that the exponential slope is given by r = a • exp (b • X), with X = x or X = c + dx + ex2 + fx3, x which is a linear coordinate which starts with X = 0 at the outlet of the nozzle, r which is the radius of the nozzle a, b, c, d, e, f are coefficients.

30. A unit of the medicament according to claim 29, characterized in that the coefficients are selected to give an exponential function with a point of inflection.

31. A unit of the medicament according to claim 24, characterized in that the second region is made of a soft plastic and at least a part of the nozzle is surrounded by a ring made of a hard material on the outside of the nozzle.

32. A housing unit for hypodermic injections, characterized in that it comprises a first region which is compressible or flexible and which is formed by a wall material, - a second region having at least one orifice, liquid medicament, - a closure for closing at least one orifice, an explosion chamber in which the first region is located, a gas generator located in the explosion chamber to generate a pressure inside the explosion chamber, wherein the first and second regions are made of separate pieces.

33. A unit of the medicament for use in hypodermic injections with a first segment and a second segment fixed together to form a cavity for the liquid medicament, characterized in that the second segment has a concave portion which flexes outward when pressure is applied to the liquid. first segment.

34. A unit of the medicament according to claim 33, characterized in that the first segment has a convex portion.

35. A unit of the medicament according to claim 33, characterized in that the first and the second segment are soldered together and the medicament unit has a thickened portion that annularly surrounds the cavity to ensure that the first and second segment are suitably welded together.

36. A handling unit for hypodermic injections, characterized in that it comprises - a first coating providing an explosion chamber and an explosive therein, a second coating with a piercing needle disposed therein, a medicament unit having a concave portion and which is interposed between the first and the second lining wherein the concave portion must be arranged below a pointed end of the needle and the pressure applied to the unit of the medicament generates a bending deformation of the concave portion leading from this way to a perforation of the medication unit.

37. A handling unit according to claim 36, characterized in that the medicament unit comprises a convex portion in its first segment which prevents perforation of the first segment when the drug unit is deformed under pressure.

38. A handling unit according to claim 36, characterized in that the second coating has a recess for receiving a unit of the medicament therein and supporting the second segment to prevent deformation of the second segment with the exception of the concave portion.

39. A handling unit according to claim 36, with a space generated by the concave portion of the medicament unit and the second coating, characterized in that the handling unit comprises a ventilation hole which allows the gas to escape from the space when the concave portion moves in the direction toward the second liner.

40. A hypodermic injection system, characterized in that it comprises - a unit of the medicament in which the liquid to be injected is stored and which has a first and a second region, the first compressible or flexible region and the second region having at least one orifice, an explosion chamber in which the medicament unit is located at least partially and a pressure generated within the explosion chamber deforms the first region of the medicament unit, an activatable gas generator, located within the chamber of exposure that generates a pressure inside the explosion chamber when activated, where the explosion chamber has a vent hole which allows the gas to escape from the explosion chamber in a controlled manner.

41. A hypodermic injection system according to claim 40, characterized in that the flow resistance of the system for the combustion gases is adapted to provide a desired pressure on the time curve which leads to the appropriate injections.