SK288151B6 - Three-chamber automatic injector - Google Patents

Abstract

Injector for mixing, dissolving and administering a medicament stored in mutually separated chambers, said injector consisting of a body (1) the cavity of which contains a pushing mechanism and a freely disposed replacement insert (7) comprised of a hollow cylinder being separated by means of three pistons into three chambers (19, 18 and 30).An injection needle (16) is arranged within the third chamber (30) guide cylinder (17) located below the third piston (12). A plug (13) closes the third chamber (30) of the replacement insert (7) and a union nut (6) closes from below the body (1) cavity. The pushing mechanism consists of a pull rod (2), a compression spring (3) and a safety (4). The safety (4) is located on the upper portion of the body (1) cavity bottom (27). The compression spring (3) is inserted on the pull rod (2). The pull rod (2) is provided in its upper section with two stops (24 and 25) for successive fall down of the pull rod (2) through an opening (28) performed in the safety (4) into a first working position and a second working position.

Description

Technical field

The invention belongs to a group of devices which inject liquids into a living organism in cases where it is necessary to inject the drug immediately and under conditions not known in advance. The invention relates to a three-chamber automatic injector with mutually separated chambers in which the individual components which are mixed prior to injection are stored.

BACKGROUND OF THE INVENTION

A number of manual and automatic devices are now known to allow injection of a drug solution into a patient's body or other receiving device. Furthermore, there are cases in which certain persons need to inject a drug solution at a time that cannot be predicted. These persons should be equipped with injectors which can be activated in a simple and rapid manner and which are reliable. For these cases, automatic injectors have been developed. They should meet the storage requirement for several years without changing the chemical or pharmacological properties of the ingredients they contain, regardless of the storage temperature. Furthermore, these automatic injectors are exposed to harsh conditions during the time they are worn by potential users. In addition to the shelf life of the automatic injectors, their durability under the conditions to which they are exposed prior to application is equally important. In this context, it should be noted that the stability of the drug solutions may deteriorate during prolonged storage. This is the case with nerve gas antidotes that are stable in powder form, but are difficult to stabilize in solution over a long shelf life. Thus, there is a need for a multi-chamber automatic injector for injecting drug solution that is functionally simple, fast and reliable, in which components can be stored separately over a long period of time to form a drug solution upon mixing, and which includes a mechanism that mixing the ingredients and then applying their solution.

A number of patents of similar devices are known, e.g. YU-P-616/88. Its disadvantages include the need for five steps in the prescribed order preceding the actual activation. This reduces its reliability and the possibility of rapid use in unexpected and unfavorable conditions. Another known device described in EP-A 0 219 899 has the disadvantage that it is intended as a disposable device. If the auto-injector is used, the drug cartridge cannot be replaced and the automatic injector must be discarded after use. A further disadvantage of this device is that the bypass coupling is provided outside the drug insert, requiring a large inner diameter of the auto-injector and other cartridges allowing the insert to be telescopically moved in the body of the automatic injector.

Other disadvantages of said auto-injectors are the need to grip them prior to application with both hands in order to remove the needle cover, perform a screw motion or exert some force resulting in subsequent mixing of the separate components and triggering the injection device. Significant disadvantages also include the fact that the mixing of the separate components and the actual injection of the drug is not carried out by successive steps of one type of activity, but is composed of different activities, e.g. telescopic insertion of the body of the auto-injector results in mixing of the components and consequently unlocking of the drug delivery drive device, mostly by releasing the latch on the spring-loaded rod.

In summary, known devices for injecting one, two or more component medicaments into the body have the disadvantage that the actual administration of the medicament is preceded by the need to perform a series of steps in order to mix the separate components and to start the autoinjection device. Further disadvantages are that these auto-injectors do not provide protection of the injection needle from contamination, that they do not allow the auto-injectors to be used repeatedly, that they do not allow rapid mixing of the liquid and powder components that their individual securing elements have to be removed before using the auto-injectors have very small dimensions , which hinders the preparation of auto-injectors under stressed conditions.

SUMMARY OF THE INVENTION

A three chamber automatic injector for mixing and administering medicament stored in separate compartments consisting of a push mechanism and an injector body, the cavity of which contains separate compartments filled with solutions and / or powder of the pharmaceutical active substance with a syringe. above which the pushing mechanism is disposed and is separated from the second chamber by a second piston, the second chamber houses a bypass clutch of the second piston, the third piston separates the second chamber and the third chamber, in which the injection cylinder is attached in the guide cylinder below the third piston a needle, the guide roller is provided at the top with passages that connect 2 to the third chamber with the mouth of the injection needle, the third chamber consisting of a first chamber and a second chamber, the second chamber having a diameter of 5-10% larger than the diameters of the first chamber and the second chamber and its length is shorter than the sum of the heights of all three pistons, the second space is closed at the bottom under the tip of the needle by a blanking plug, according to the invention is that the pushing mechanism consists of a rod, compression spring and fuse, fuse is located on top the upper part is equipped with two stops for the gradual passage of the rod through the hole formed in the fuse into the first working position and the second working position, and in the cavity of the injector body there is a free insert consisting of a hollow cylinder of three pistons divided into three chambers, and in the third chamber, a syringe needle is attached in the guide cylinder located below the third piston, the diameter of the guide cylinder is smaller than the diameter of the pistons, the second chamber houses the second piston bypass coupling; the cap is closed and the body cavity is closed from below by a union nut.

The fuse is covered with a cover in which it moves slidingly, the cover is firmly connected to the body or the fuse is located on the upper part of the bottom of the body cavity rotating and at the same time forms the cover.

The bypass coupling is formed by a circumferential recess section or groove in the inner wall of the second cartridge insert having a larger diameter than the diameter of the second piston, or the bypass coupling is formed by a section with leakage channels parallel to the body axis formed with gradual recess in the axial direction in the inner peripheral wall of the insert.

The third piston is provided on its face with a recess for receiving the guide cylinder.

The plug touches the union nut, which is provided with an opening for the injection needle passage.

If necessary, to mix more substances that require separate storage prior to injection, both the number of chambers in the cartridge and the number of stops on the rod can be increased.

A three-chamber automatic injector is a device that makes it possible to automatically inject a drug solution that results from separately placed three or more components in the insert. With these components separated, the injector can be stored for several years without changing their chemical or pharmacological properties. The automatic injector according to the invention is simply operated with the thumb of one hand. Moving the fuse from one working position to another will start the mixing phase of one component with the other. In the case of a more than three-chamber design with a back-up of the fuse, the mixing phase of the next component placed in the next chamber with the drug solution formed in the previous working phase is started. After all components have been mixed, a further movement of the fuse triggers the phase of injecting the drug solution into the body or other receiving device. At the beginning of this phase, the injection needle is pulled out and the drug solution formed is applied. The automatic injector is again ready for use when the compression spring of the push mechanism is pushed back, the rod is locked, the new insert with separate components is inserted and locked by the union nut.

The advantage of the three-chamber automatic injector according to the invention is, in particular, the ease of handling and use of the auto-injector even under unfavorable conditions. The injection needle is protected before use by a cartridge and a blanking plug. It is not necessary to remove any needle shields prior to administration, as in the prior art injectors. The phase of mixing, dissolving the active ingredient and injecting the drug into the body can be controlled with one hand. The number of steps required to prepare and start the auto-injector and to mix the liquid component and the powder component takes 3 seconds.

The force exerted on the injector is minimal.

The cartridge with separate components of the solutions and the powder allows long-term storage of the components in the different states required for their chemical or pharmacological stability.

The insert is replaceable and allows multiple use of the injector mechanism itself.

The design of the stops and the rod and fuse is very simple and ensures a high reliability of the drawbar overflow in the first and second working positions.

The manufacture and assembly of the autoinjector is simple and the manufacturing costs are low.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a longitudinal section of an automatic injector prior to use.

Fig. 2 shows a longitudinal section of the automatic injector after the fuse has been moved to the first operating position in which the liquid component and the powder component are mixed.

Fig. 3 shows a longitudinal section of the automatic injector after the fuse has been moved to the second operating position when the drug solution is moved to the space from which it will be applied.

Fig. 4 shows a longitudinal section of an automatic injector after application of a drug solution to an organism or other receiving device.

Fig. 5 shows a plan view and a side view of a rod with a system of stops formed on its shaft.

Fig. 6 shows a plan view and a side view of the fuse.

Fig. 7 shows a detail of the central part of the insert with the passage channels in a 5: 1 scale. Fig. 8 shows a detail of the bottom of the liner at a 5: 1 scale.

DETAILED DESCRIPTION OF THE INVENTION

The three-chamber automatic injector shown in the figures consists of a hollow cylindrical body 1, in the upper part of which there is a push mechanism consisting of a drawbar 2, steel compression springs 3 and a fuse 4. A cap 5 securing the fuse 4 is attached to the upper part of the barrel 1. .

An insert 7 with separate chambers 19, 18 and 30 filled with solutions and / or powder of the pharmaceutical active substance is inserted into the cavity of the cylindrical body 1. The liner 7 is secured in the body and underneath by a union nut 6. The lower widened portion 26 of the drawbar 2 is supported by a first piston 11, which is closed from above both the liner 7 and the first chamber 19. This chamber 19 is separated from the second chamber 18 by a second In the cylindrical wall of the second chamber 18, leakage channels 14 are provided, which are provided with a leading edge 15 allowing the piston 11 to pass smoothly through this edge 15. The third, last piston 12 separates the second chamber 18 and the third chamber 30 in which A syringe needle 16 is attached in the guide roller 17 located below the third piston 12. The diameter of the guide roller 17 is smaller than the diameter of the pistons 10, 11 and 12. The guide roller 17 is provided at the top with passageways 22 connecting the outer space of the guide roller 17 and the third. a chamber 30 with an orifice of the injection needle 16. The third chamber 30 is formed by a first chamber 20 and a second chamber 21 which is at the bottom below the tip The second space 21 has a diameter 7% larger than the diameter of the other chambers of the insert 7. The plug 13 touches the previously described union nut 6. The push rod 2 is formed by a stem 23 and is provided with a first stop at the top 24 and a second stop 25. The lower part 26 of the shank 23 is extended, a steel compression spring 3 is mounted on the rod 2, which is supported at one end against the lower enlarged part 26 of the shank 23 and the other upper end abuts the bottom 27 of the cavity 1. a fuse 4 is located at the top of the bottom 27 of the body cavity 1, through which the stem 23 of the drawbar 2 with stops 24 and 25 passes. The drawbar 2 further extends through the cavity of the cylindrical body 1. opening 28, for the overflow of the first stop 24 of the drawbar 2 in the first working position of the fuse 4 and for the overflow of the second stop 25 of the drawbar 2 at the second working position The fuse 4 and the upper end of the rod 2 are covered by a cover 5 which is fixedly connected to the upper side of the bottom 27 of the cavity of the body 1.

In the first chamber 19 there is a solvent necessary to form a drug solution from the powder component, which is located in the second chamber 18 in the middle part of the liner 7 between the pistons 11 and 12. The third chamber 30 is filled with a suitable liquid and gas phase. The described three-chamber injector in an arrangement in which it is stored and ready for use is shown in FIG. First

The injector can be operated with one hand by sliding the lock 4 from the rest position (Fig. 1) to the first working (mixing) position (Fig. 2). By moving the fuse back (the second fuse working position is the same as the starting position), the injector gets into the second working position (injection) (Figs. 3 and 4).

By sliding the fuse 4 from the rest position to the first working position, the first stop 24 of the draw 2 will fall through the opening 28 in the fuse 4 by pushing the spring 3 on the draw 2 to move the first piston 10 and apply hydraulic pressure to the second piston 11. with a bypass coupling 29 which is formed by leakage channels 14 formed in the inner circumferential wall of the chamber 18 parallel to the axis of the body 1. The length of the channels M is equal to five quarters of the height of the second piston 11.

The pressure on the third piston 12 is partially compensated by the gas layer in the third chamber 30 in the first chamber 20. Through the passageways 14, liquid from the first chamber 19 enters the second chamber 18, where it dissolves the powdered medicament form (Fig. 2).

The length of the travel of the first piston 10 and the second piston 11 depends on the distance of the first stop 24 and the second stop 25.

By moving the fuse 4 to the opposite, second operating position, or in this case to the original rest position, the second stop 25 will fall through the opening 28 of the fuse 4 and the push rod 2 will push the plunger 10 up to the plunger 11. 13 (FIG. 3). Further, the pistons 10 and 11 are moved to the piston 12 (FIGS. 4 and 8).

When the plug 13 is pierced, the gas phase leaks through the passages 20 formed in the guide cylinder 17 into the mouth of the injection needle 16. Subsequently, the solution from the third chamber 30 from the first chamber 20 enters the injection needle 16.

When the piston 12 arrives in the expanded space 21, all of the described spaces, which were created in the individual working phases, are brought together in one common. The contents of the third chamber 30 are mixed with the solution from the second chamber 18.

The drug solution flows through the passages 22 at the top of the guide roller 17 into the mouth of the injection needle 16 and through it into the body or other receiving device.

In FIG. 4 shows the position of the individual parts of the automatic injector, and FIG. 8 shows a detail of the bottom of the insert 7 at a scale of 5: 1 after application of the drug solution. In FIG. 5 shows the drawbar 2 and FIG. 6 a fuse 4 for a three-chamber version of an automatic injector.

Thus, the individual required phases in the operation of the automatic injector, which, in the case of a three-chamber embodiment, are to form a drug solution from a liquid and solid component in the form of a powder and subsequently inject it into an organism or other receiving device.

The internal by-pass coupling allows immediate mixing of the powder and liquid components. Further mixing and homogeneity of the injected active ingredient is ensured by widening the diameter of the second space 21 in the third chamber 30 and the turbulence in the passages 22.

The injection needle 16 is protected from use by the insert 2 and the blanking plug 13. Prior to administration, it is not necessary to remove the optional needle cover, as is the case with the prior art injectors.

The design of the stops 24 and 25 of the drawbar 2 and the fuse 4 is very simple and guarantees high reliability of the drawdown of the drawbar 2 by the fuse 4 in both the first and second working positions.

Industrial usability

The three-chamber automatic injector according to the invention is useful in the pharmaceutical industry for the preparation of a medicament for crisis situations.

Claims (7)

PATENT CLAIMS A three-chamber automatic injector for mixing and administering a medicament stored in separate compartments comprising a push mechanism and an injector body, the cavity of which comprises separate compartments filled with solutions and / or powder of the pharmaceutical active substance with a syringe, the first compartment prior to use. above) closed by a first piston (10) over which a pushing mechanism is located and separated from the second chamber (18) by a second piston (11), in the second chamber (18) a bypass coupling (29) of the second piston (11), a third the piston (12) separates the second chamber (18) and the third chamber (30) from which the injection needle (16) is attached in the guide cylinder (17) below the third piston (12), the guide cylinder (17) being the upper chamber through the passages (22) connecting the third chamber (30) to the mouth of the injection needle (16), the third chamber (30) consisting of a first chamber (20) and a second chamber (21), a second chamber the space (21) has a diameter of 5 to 10% larger than the diameters of the first chamber (19) and the second chamber (18) and its length is shorter than the sum of the heights of the three pistons (10, 11 and 12); (21) is closed at the bottom under the tip of the needle (16) by a blanking plug (13), characterized in that the pushing mechanism consists of a rod (2), a compression spring (3) and a fuse (4); located on the upper part (27) of the body cavity (1), on the rod (2) a compression spring (3) is fitted, in the upper part the rod (2) is equipped with two stops (24 and 25) through the opening (28) formed in the fuse (4) to the first working position and to the second working position, and in the cavity of the injector body (1), there is a loosely displaceable insert (7) consisting of a hollow cylinder with three pistons divided into three chambers (19, 18 and 30), in the third chamber in the guide cylinder (17) located under the third piston (12), an a needle (16), the diameter of the guide cylinder (17) is smaller than the diameter of the pistons (10, 11 and 12), in the second chamber (18) a bypass coupling (29) of the second piston (29) is located in the inner wall of the hollow cylinder 11), the third chamber (30) of the insert (7) is closed by a plug (13) and the cavity of the body (1) is closed from below by a union nut (6). A three-chamber automatic injector according to claim 1, characterized in that the fuse (4) is covered by a cap (5) in which it moves slidingly, the cap (5) being fixedly connected to the body (1). The three-chamber automatic injector according to claim 1, characterized in that the fuse (4) is located on the upper part (27) of the cavity of the body (1) rotatable and at the same time forms the cap (5). The three-chamber automatic injector according to claims 1 to 3, characterized in that the bypass coupling (29) is formed by a circumferential recess or groove section in the inner wall of the second chamber (18) of the insert (7) having a larger diameter than is the diameter of the second piston (11). A three-chamber automatic injector according to claims 1 to 3, characterized in that the bypass coupling (29) is formed by a section with throughflow channels (14) parallel to the axis of the body (1) formed with gradual recess (15) in the axial direction the peripheral wall of the insert (7). A three-chamber automatic injector according to claims 1 to 5, characterized in that the third piston (12) is provided on its face with a recess for receiving the guide roller (17). A three-chamber automatic injector according to claims 1 to 6, characterized in that the plug (13) contacts the union nut (6), which is provided with an opening for the passage of the injection needle (16).