Wet/dry automatic injector assembly

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DESCRIPTION

Automatic wet / dry injection set.

The present invention relates to an automatic injection device containing a pre-filled drug load to automatically self-administer the drug when the device is actuated.

The present invention relates generally to automatic injectors for providing medication at an injection site, and in particular, the present invention is directed to an automatic injector assembly for rapidly combining a liquid material with a dry material to form a liquid medication. to deliver the drug at an injection site. In accordance with one embodiment of the present invention, the autosampler assembly includes a pair of plunger assemblies movable within the injector assembly to pressurize the liquid injection solution and compress the dry drug.

An automatic injector is a device to allow a person to self-administer a dose of medicine into their body. The medicine is usually stored in liquid form. The advantage of automatic injectors is that they contain a metered dose of a liquid medicine in a sealed, sterile capsule and that they can be used to introduce the medicine into the body in emergency situations. Another advantage of automatic injectors is that self-administration is performed without the user initially seeing the hypodermic needle through which the drug is injected and without the user having to manually force the needle into their flesh.

There are drawbacks associated with storing medications in liquid form. Some medications are not stable in liquid form. Additionally, some liquid medications typically have a shorter shelf life than their solid counterparts. Some have developed automatic injectors that store the drug in solid form and a liquid injection solution. Those injectors, described for example in the newly granted US patent No. 35,986, entitled "Multiple Chamber Automatic Injector", require, however, that the user of the injector accelerate dissolution of the solid component by manually shaking the liquid component and the solid component immediately prior to injection. This lengthens the time needed to administer the drug dose. Also, improper mixing of the drug with the liquid injection solution can release an insufficient dose of the drug. There is a need for an automatic injector that stores the drug in a solid form that does not require manual premixing by the user. In addition, rapid administration of the drug is needed for emergency medical situations (eg, nerve gas and chemical agent poisoning).

In EP-A-0361668, for example, an automatic injector is described which has at least two chambers containing different ingredients of a drug, separated by an impermeable membrane. A lancet can be moved independently of a plunger to cut or pierce the membrane before a spring loaded actuating member for the plunger is released to drive a needle out of the injector body and discharge the drug through the needle. The injector, however, is arranged in such a way that a two-step activation process is required to mix the ingredients and then discharge the mixed ingredients.

In EP-A-1292343, which is prior art only in accordance with Article 54 (3) of the EPC, an automatic injection device is described that contains a pre-filled load of medicine to automatically self-administer the medicine by actuation thereof. .

In accordance with the present invention, there is provided an automatic injection device containing a pre-filled load of medicament to automatically self-administer the medicament by actuation thereof, said automatic injection device comprising: a housing assembly; a dry compartment located within the housing for storing a predetermined dry load of dry medicament within it; a wet compartment located within the housing for storing a predetermined amount of liquid injection solution therein; an activation assembly for pressurizing the liquid injection solution in the wet compartment, wherein the activation assembly allows the passage of the liquid injection solution from the wet compartment to the dry compartment by activating the automatic injection device, wherein the activation assembly includes a first pressure element that applies pressure to the liquid injection solution within the wet compartment by activating the automatic injection device; and a needle assembly for dispensing the liquid injection solution containing the drug dissolved therein; characterized in that: the activation assembly includes: a second pressure element that compresses the dry medicine within the dry compartment by activating the automatic injection device, and a connecting member to transmit a force from the first pressure element to the second pressure element; wherein, in use, a single actuation causes the trigger assembly to mix the dry drug and the liquid injection solution and dispense the liquid injection solution containing the drug through the needle assembly.

In response to the foregoing challenges, applicants have developed an innovative automatic injection device that has both wet and dry compartments. The preferred embodiment provides an automatic injection device containing a pre-filled load of medication to automatically self-administer the medication by actuation thereof. The injection device includes a housing assembly, a dry compartment located within the housing for storing a predetermined dry load of dry medication within the housing, and a wet compartment located within the housing for storing a predetermined amount of liquid injection solution within he. The injection device further includes an activation assembly that allows pressurization of the liquid injection solution in the wet compartment. The activation assembly also makes it possible to compress the medicine

ES 2 249 486 T3 dry inside the dry compartment by activating the automatic injection device. Compression of the drug occurs regardless of the application of pressure on the liquid injection solution. The activation assembly further facilitates the passage of the liquid injection solution from the wet compartment to the dry compartment by activating the automatic injection device. The injection device further includes a needle assembly for dispensing the liquid injection solution containing the drug dissolved therein.

In accordance with one embodiment of the present invention, the activation assembly includes a first pressure element that applies pressure to the liquid injection solution within the wet compartment by activating the automatic injection device. The activation assembly includes a second pressure element that compresses the dry drug into the dry compartment by activating the automatic injection device. The second pressure element provides a barrier between the wet compartment and the dry compartment to prevent transfer of the liquid injection solution from the wet compartment to the dry compartment prior to activation of the automatic injection device.

The activation assembly may further include a connecting member to transmit a force from the first pressure element and a collar to the second pressure element to facilitate compression of the dried medicament. It is provided that the first pressure element is frictionally applied to the connecting element to apply a force from the first pressure element to the connecting element. The application of pressure to the second pressure element by means of the connecting element occurs in such a way that the dried medicine can be compressed prior to pressurization of the liquid injection solution. The connecting element is slidably received within an opening within the first pressure element. The connecting element is adapted to make or be in contact with the second pressure element. The connecting element may include a stepped surface or have a slight diameter variation in the stem of the connecting element such that the first pressure element contacts the stepped surface / variable diameter to initially actuate the second pressure element, which ensures pressure on the dry medicine. The force of the spring assembly may be sufficient to overcome the forces associated with varying the diameter of the connecting element, whereby the first pressure element slides along the connecting element to pressurize the liquid injection solution and force the solution to enter the dry compartment.

In accordance with one embodiment of the present invention, pressurizing the liquid injection solution in the wet compartment may include applying a force to a first pressure element within the wet compartment. Compressing the dry medicine into the dry compartment may include transferring a force from the first pressure element to a second pressure element, and compressing the dry medicine with the second pressure element. Opening the fluid path between the wet compartment and the dry compartment may include moving the second pressure element from a first position to allow passage of the liquid injection solution from the wet compartment to the dry compartment around the second element. pressure.

Preferred embodiments of the present invention provide an automatic injector device that stores medicine in liquid form to increase shelf life, an automatic injector device that automatically mixes a solid medicine with a liquid injection solution upon activation, an injector device automatic that pressurizes a stored liquid injection solution by activating the automatic injector device, an automatic injector device that compresses dry medicine by pressurizing the stored liquid injection solution, an automatic injector device that minimizes residual space within the injector device to limit plugging of dry medicine, and an automatic injector device that allows injecting a medicine without shaking the autosampler device.

The invention will be described in conjunction with the following drawings, in which the same reference numbers designate homologous elements and in which:

Figure 1 is a cross-sectional side view of a wet / dry autosampler assembly in accordance with the present invention.

Figure 2 is a partial schematic cross-sectional view of the wet / dry autosampler assembly of Figure 1; and Figure 3 is a cross-sectional side view of a wet / dry autosampler in accordance with another embodiment of the present invention. Detailed description of the invention

Referring now more particularly to the figures, an automatic injector assembly 10 is shown in Figure 1. The present invention is described in relation to a push button type injector in which the user removes an end cap assembly. and presses a button to start the injection process. The present invention, however, is not limited to push-button type automatic injectors; rather, it is envisaged that the present invention may be incorporated into a tip activated autoinjector, as described, for example, in US Patent No. 5,658,259. It is further envisioned that the present invention may be adapted for use in a syringe or the like for administering a dose of medicament. The present invention is directed to an assembly that provides a low-residue system with little dead space that can retain liquid and / or drug.

The autosampler assembly 10 includes a generally hollow housing 110. Housing 110 includes an insertion and injection end 111 and activation end 112, as shown in Figure 1. An actuation assembly 120 extends from an opening 113 in the activation end 112 of housing 110. The actuator assembly actuator 120 is slidably received within housing 110. A removable end cap assembly 130 is removably secured to the assembly.

ES 2 249 486 T3 of actuator 120. When end cap assembly 130 is secured to actuator assembly 120, a side portion 131 of end cap assembly 130 is adapted to abut housing 110 to prevent displacement of the assembly. actuator 120 and an unintended injection of the drug.

Actuator assembly 120 includes push button actuator assembly 121 having a hollow interior. End cap assembly 130 engages push button actuator assembly 121. A collar 122 is located within the hollow interior of push button actuator assembly 121. An inner tube 123 is also located within the hollow interior of the assembly. push button actuator 121. Inner tube 123 is adapted to contact collar 122, as shown in Figures 1 and 2. An opposite end of inner tube 123 may include a coupling rib 1231 that is adapted to be received within a complementary recess 1211 within push button actuator assembly 121. An actuator assembly 124 is located within a space formed between collar 122 and inner tube 123. A pin 132 extends from end cap assembly 130 and is received within collar 122 to prevent or block collapse of collar 122 prior to activation.

The user removes the end cap assembly 130. The pin 132 no longer prevents movement of the collar 122. By depressing the actuator assembly 121, the actuator assembly 124 provides the necessary force when activated to operate the injector to inject into the user the necessary dose of medicine. It is envisioned that the drive assembly 124 may be a spring assembly, a compressed gas assembly, or any other suitable energy storage device. When activated, drive assembly 124 causes collar 122 to move such that a needle assembly 140 extends from an opening in injection end 111 of housing 110. The displacement of collar 122 also causes the dry drug to mix with the liquid injection solution, described in more detail below. Prior to activation, there is no pressure on the dry drug within the dry container 160.

One end 1221 of collar 122 extends into a wet container 150 located within housing 110 to contain the liquid injection solution. End 1221 of collar 122 is adapted to contact a first plunger assembly 170 located within wet container 150. The first plunger assembly 170 is adapted to engage the side wall of the wet container 150 to prevent leakage of the contents (eg, liquid injection solution) of the wet container 150 from the actuation end 112 of the housing 110. First plunger assembly 170 is preferably formed from a material that has low friction properties such that collar 122 and first plunger assembly 170 can easily slide within wet container 150 when operated. Alternatively, the first plunger assembly 170 may be lubricated with silicon or other suitable non-reactive lubricants. The displacement of the collar 122 and the first plunger assembly 170 pressurizes the liquid within the wet container 150.

The first plunger assembly 170 includes a center passage 171 extending through it, as shown in Figure 1. Extending through the center passage 171 is a lancet assembly 180. The lancet assembly 180 extends through of the wet compartment 150 and is adapted to contact a second plunger assembly 190 that separates the wet compartment 150 from the dry compartment 160. The stem 181 of the lancet assembly 180 is capable of moving within the collar 122 such that the entire volume of liquid within the wet compartment 150 can be passed into the dry compartment 160. A suitable medication is located within the dry container 160. It is It is envisaged that the dry medicine can be in the form of powder or freeze-dry. To aid in mixing the dry medication with the liquid injection solution contained in the wet container 150, it is desirable that the medication be compressed while mixing with the liquid injection solution in the dry container 160. The second plunger assembly 190 prevents mixing the dry drug and liquid injection solution prior to activating the autosampler assembly.

The second plunger assembly 190 forms a barrier between the wet compartment 150 and the dry compartment 160. The second plunger assembly 190 is adapted to engage the side wall of the wet container 150 to prevent passage of contents (eg, solution). injection) from the wet container 150 into the dry compartment 160 prior to activation of the automatic injection assembly. The second plunger assembly 190 is preferably formed from a material that has reduced friction properties such that the second plunger assembly 190 can slide easily when operated. Alternatively, the second plunger assembly 190 may be lubricated with silicon or other suitable non-reactive lubricant. The displacement of the second plunger assembly 190 compresses the dry medication within the dry container 160 and opens a path for fluid between the wet and dry compartments 150 and 160.

During operation, spring assembly 124 releases collar 122, which applies pressure on first plunger assembly 170. Applying pressure on first plunger assembly 170 displaces first plunger assembly 170 in the direction of the piston assembly. needle 140. First plunger assembly 170 drives lancet assembly 180 such that first plunger assembly 170 and second plunger assembly 190 travel together until medication is compressed. The first plunger assembly 170 frictionally engages the lancet assembly 180, through the center passage 171, causing the lancet assembly 180 to also travel in the direction of the needle assembly 140. The passageway 171 can be applied to an enlarged diameter section or stepped portion on stem 181 of lancet assembly 180. When contacted, lancet assembly 180 moves second plunger assembly 190 toward needle assembly 140. This displacement of the second plunger assembly 190 compresses the dry drug located within the dry compartment 160 and opens a passageway.

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200 for liquid between the wet compartment 150 and the dry compartment 160. The first plunger assembly 170 then travels along the stem 181 of the lancet assembly 180 to pressurize and drive the liquid into the dry compartment 160. The passageway 200 to Liquid may include recesses formed in the side wall of wet compartment 150 and dry compartment 160, which open when second plunger assembly 190 is displaced. It is envisaged that the passageway 200 for liquid can be formed by a reduced space between the wet container 150 and the second piston assembly 190, by a series of bypass grooves, by a variation of the diameter of the compartments, by ribs of the container that distort the second plunger assembly or by any other assembly that is capable of allowing the flow of the liquid injection solution around the second plunger assembly 190.

The displacement of the collar 122 under the force of the spring assembly 124 continues to displace the first plunger assembly 120 toward the needle assembly 140. In this way, the liquid injection solution remains under pressure when the volume of the wet compartment 150 decreases due to upon displacement of the first plunger assembly 170. As the first plunger assembly 170 travels along the lancet assembly 180, the frictional forces between the first plunger assembly 170 and the lancet assembly 180 continue to act on the lancet assembly 180, which applies pressure on the second plunger assembly 190. With this arrangement, the dry drug within dry compartment 160 remains under compression. By keeping the drug dry under compression during injection, dissolution of the solid drug into the liquid injection solution is accelerated. Furthermore, this prevents the liquid injection solution entering the dry container 160 from forming channels within the dry drug, which would prevent dissolution of the drug within the solution. In this way, the liquid injection solution containing less than the necessary dose of medication could be injected into the user.

For the autosampler assembly to operate effectively, the frictional forces between the second plunger assembly 190 and the side wall of the wet container 150 and the dry container 160 must be less than the frictional forces between the first plunger assembly 170. and lancet assembly 180.

The liquid injection solution mixed with the medication may then exit the dry compartment 160 through the needle assembly 140 opposite the wet compartment 150. A medication support assembly 210 may be located adjacent to the needle assembly 140 to prevent some Undissolved medication enters needle assembly 140. Holder 210 may include a filter, which may be a porous material.

As discussed above, displacement of collar 122 and driver assembly 124 causes injection needle 141 of needle assembly 140 to advance and protrude through housing 110. Drug injection can be accomplished by a simple operation. The user simply removes the end cap assembly 130, positions the injection end of the housing 110 adjacent to the injection site, and depresses the push button actuator assembly 121. This operation automatically initiates the operation of drive assembly 124 to advance collar 122, which advances first plunger assembly 170, lancet assembly 180, and second plunger assembly 190, causing the positioned liquid injection solution inside wet compartment 150 enter dry compartment 160. The dissolved drug is then transmitted through injection needle 141 to provide the user with the necessary dose of drug. The automatic injector according to the present invention reduces the time required to deliver medicine compared to other wet / dry injectors. The present invention eliminates the need for the user to mix.

It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope of the present invention. For example, it is envisaged that a cover assembly, described, for example, in US Patent No. 5,295,965, may be secured to the injection end of housing 110 after drug is administered. In addition, the autosampler may also include a nozzle plunger assembly, as described, for example, in US Patent 5,465,727. It is also envisioned that the lancet assembly 180 may be connected to the second plunger assembly 190 such that the dried medicament is compressed when the lancet assembly 180 is displaced. The first plunger assembly 170 may include a membrane 171 that is applied to the plunger assembly 170 or forms part of the plunger assembly 170, as shown in Figure 3. When a force is applied, the stem 181 of the lancet assembly 180 passes through membrane 171. This provides an additional barrier that provides better sterility. Thus, the present invention is intended to cover modifications and variations of the invention, provided they are within the scope of the appended claims.